Process of making phonograph-needles.



ROSCDE C. JOHNSTON, OF ST. LOUIS PARK, MINNESOTA, ASSIGNOR 0F EMILNELSON, OF MINNEAPOLIS,

ONE-HALF TO MINNESOTA.

PROCESS OF MAKING PHONOGRAPH-NEEDLES.

No Drawing.

1 '0 all whom it "my concern:

Be it known that I, Roscoe C. JoHNsroN, a citizen of the United States,residing at S1. Louis Park, in the county of Hennepin and State ofMinnesota, have invented a new and useful Process of MakingPhonograph-Needles, of which the following is a specification.

The process forming the subject matter of this application, is adaptedto be employed in the preparation of a non-metallic reproducing needlefor phonographs, whether the needle be made of wood or of bone.

The invention aims, further, and specifically, to provide a novelprocess for treating a bone needle.

It is the object of the invention to produce a non-metallic needle ofthe kind above menafter described, and in the various steps thereof, itbeing understood that, within the scope of what is claimed, changes maybe made without departing from the spirit of the invention.

his invention contemplates the treatment of a her wood needle. Althoughthe process may be used to advantage in treating many different kinds ofWood, and in par- Wood, in the making of it is of peculiar utility inconnection with a needle made of English or American box wood, it havingbeen ascertained by experiment, that the grain of English or American oxwood differs from the grain of other hard woods sul'lieiently to renderbox of peculiar utility, notably when employed in connection with theprocess hereinafter described.

In putting the present invention into practice, a hard wood needle ofany desired shape is immersed in a siccative oil, or is otherwisetreated therewith. In practice, it is preferable to immerse the needlein the oil, and the oi, preferably. is at boiling inseed oil ispeculiarly eflineedle has been immersed in boiling linseed oil for avarying period of time, ordinarily about thirty minutes, the needle isremoved Specification of Letters I'atent.

Patented May 21, 1918.

Application filed May 5, 1917. Serial No. 166,644.

from the boiling oil and is dried. The needle ma y be permitted to dryin the air at the prevailing atn'iospherie temperature, but, under someconditions, depending upon the particular character of the wood whichhas been treated, it may be desirable to bake the needle slowly in anoven, at a low oven temperature. The length of time that the needle isbaked, if it is found desirable to bake the needle, will vary, butordinarily, the baking step is carried on for a period of about twohours.

A needle produced by the process above described will give a medium toneof peculiar distinctuess and clarity. A needle produced by this processwill not injure the record and may be used many times withoutresharpening.

The oil fills the pores of the needle, and when hardened by drying,either at atmosp eric temperature or in an oven, results in theproduction of a needle having the charactc-ristics helei before setforth.

The invention contemplates the treatment of a phonograph n edle made ofbone. It has been proposed heretofore, to subject a bone needle to theaction of a dilute acid,

such as hydrochloric acid, for the purpose of ren'icring the earthysalts, and thentreating the needle with a grease or oil (not a sircativeoil like linseed oil) for the purpose of lubricating the needle. Such aprocess described. By treating a bone needle with a weak acid, salts areremoved but, further and unavoi ably, the physical characteristics ofthe bone are changed, depriving the bone of many of the properties whichrender it of use as a sound reprodueing medium. Further, the use of alubricating grease, such, for instance, as sperm oil, produces resultsdiffering radically from those brought about when a drying oil likelinseed oil is bone stylus has first been treated with an acid, ashereinbefore described.

In carrying out the process constituting a part of the presentapplication, a bone needle is first immersed in a weak alkaline batpreferably consisting of lye Water, which is strong enough to extractthe oil and fatt matter from the bone. The lye water bath may he eithercold or hot, and th a period of immersion may vary. If a bone needle isemployed, and notably if the immersion may immersed for a period ofapproximately one hour in a cold alkaline bath, wnsisting of week lyewater, one step of the prowess wil. have been fulfilled, although thetemperature of the alkaline both and the period of be varied.

, tl the bone needle is immersed in hot water, and preferably boilingwater, to clean the pores of the needle from the alkali-f The needle mayremain in the boiling water for a period of time which will be dictatedby the strength of the alkaline solution, and the experience of theopenutor. Ordinarily, if the needle is kept in. boiling water for a halfhour, the cleaning of the process will have been complete After theneedle has been immersed in boiling water, it may or may not be dried.Ordinarily, this drying step is not necessary, the needle being placedllniflCdlitiQlf, in u, boiling sic-satire oil, such linseed oil, and,being, kept in the boiling oil for 1t Period up roxunziting one hour,

Finally, the needle is dried, either at at iuospheric temperature or ina slow oven at a comparatively low even temperature. Two hours ofhalting will he sullicient under average Conditions.

A hone noodle treated according to the process above described producesat medium tone which is clear and distinct. The needle will not injurethe record and it will wear well, and will he found to dillerInaterially, 5o l'm' as results are concerned, from a, bone nuinlluwhich has been treated with acid and subsequently with a lubricating oilsuch as #peun oil.

l'l eving thus described the invention, what is nluimed ier--- 1. Stepsin the 'PI'OUQSS of preparing a nmi-ilmbllllP, reprodueiog, phonographneedle, which 1 111-. consist in treating the nee die with it euwy-ativuoil, and drying the nee die ul'hrr such treatment.

:L The lll'ltllltlfitKil'l mil process of pre pairing u hoiu reproduoingphonograph needle. wh ch runeiels, in treating the needle with :1 wunltalkaline solution, and then. iiiillinp; the needle with a, sieontiveoil.

l- Lr-Aiiiumiy that 11 claim the foregoing u: in own, l. lune heretoaffixed my signature in the presence of two witnesses.

ROSOOE G. JOHNSTON.

W itnossos LYNN 3071, N. I). BlGSSENY.

